<template>
  <!-- 商品分类导航 -->
  <div class="type-nav">
    <div class="container">
      <div class="nav-left" @mouseleave="isShow = false">
        <h2 class="all" @mouseenter="isShow = true">全部商品分类</h2>
        <!-- 为home组件就显示，为search就隐藏 -->
        <div class="sort" v-show="this.$route.path === '/home' || isShow">
          <div @click="goSearch" class="all-sort-list2">
            <div v-for="c1 in categoryList" :key="c1.categoryId" class="item">
              <h3>
                <!-- ✨方案一，生成了很多很多的route-link,性能很差，所以不用 -->
                <!-- <router-link
                  :to="{
                    name: 'Search',
                    query: {
                      category1Id: c1.categoryId,
                      categoryName: c1.categoryName,
                    },
                  }"
                >
                  {{ c1.categoryName }}
                </router-link> -->

                <!-- ✨方案二，不使用声明式导航，转而使用编程式导航,此时会产生一个问题，
                               绑定了太多的事件，性能也很差，所以我们使用事件委托
                 -->
                <!-- <a href="" @click="goSearch(c1.categoryId, c1.categoryName, 1)">
                  {{ c1.categoryName }}
                </a> -->

                <!-- ✨方案三，采用事件委托和自定义属性，减少绑定的事件数量 -->
                <a
                  :data-Id="c1.categoryId"
                  :data-name="c1.categoryName"
                  :data-level="1"
                >
                  {{ c1.categoryName }}
                </a>
              </h3>
              <div class="item-list clearfix">
                <div class="subitem">
                  <dl
                    v-for="c2 in c1.categoryChild"
                    :key="c2.categoryId"
                    class="fore"
                  >
                    <dt>
                      <!--✨ <router-link
                        :to="{
                          name: 'Search',
                          query: {
                            category2Id: c2.categoryId,
                            categoryName: c2.categoryName,
                          },
                        }"
                      >
                        {{ c2.categoryName }}
                      </router-link> -->

                      <!--✨ <a
                        href=""
                        @click="goSearch(c2.categoryId, c2.categoryName, 2)"
                      >
                        {{ c2.categoryName }}
                      </a> -->

                      <a
                        :data-Id="c2.categoryId"
                        :data-name="c2.categoryName"
                        :data-level="2"
                      >
                        {{ c2.categoryName }}
                      </a>
                    </dt>
                    <dd>
                      <em v-for="c3 in c2.categoryChild" :key="c3.categoryId">
                        <!--✨ <router-link
                          :to="{
                            name: 'Search',
                            query: {
                              category3Id: c3.categoryId,
                              categoryName: c3.categoryName,
                            },
                          }"
                        >
                          {{ c3.categoryName }}
                        </router-link> -->

                        <!--✨ <a
                          href=""
                          @click="goSearch(c3.categoryId, c3.categoryName, 3)"
                        >
                          {{ c3.categoryName }}
                        </a> -->

                        <a
                          :data-Id="c3.categoryId"
                          :data-name="c3.categoryName"
                          :data-level="3"
                        >
                          {{ c3.categoryName }}
                        </a>
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import { reqGetNav } from "@/api/home";
export default {
  // 组件名
  name: "TypeNav",
  // 挂载的钩子函数
  async mounted() {
    this.categoryList = await reqGetNav();
  },
  // data数据
  data() {
    return {
      categoryList: [],
      isShow: false,
    };
  },
  // 绑定事件
  methods: {
    goSearch(e) {
      // 自定义属性在事件对象上边,通过e.target.dataset获取
      const { id, name, level } = e.target.dataset;
      // 由于事件委托的机制，点击其他地方也会触发this.$router.push函数，但我们只需要
      // 点击a标签的时候触发，所以首先判断一下是否有id，有id触发，没有就return
      if (!id) return;

      const keyword = this.$route.query.keyword;

      const option = {
        name: "Search",
        query: {
          [`category${level}Id`]: id,
          categoryName: name,
        },
      };

      option.query.keyword = keyword;

      this.$router.history.push(option);
    },
  },
};
</script>

<style lang="less" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            margin: 0;
            &:hover {
              background-color: yellowgreen;
              a {
                color: #fff;
              }
            }
            a {
              width: 100%;
              box-sizing: border-box;
              display: block;
              color: #333;
              padding: 0 20px;
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          &:hover {
            .item-list {
              display: block;
            }
          }
        }
      }
    }
  }
}
</style>
